Curious Cook: How to count on food – Part 6

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If you are reading this after a meal, and you are in an Asian country, the chances are reasonably high that you have just eaten some rice or rice-based foods. If so, then you have almost certainly also ingested tiny amounts of various arsenic-based compounds, which are sort of free additives – though of course they are rather undesirable ones.

Arsenic, in various concentrations, is very common in rice because arsenic is a metalloid element found practically everywhere on the planet (it is the 53rd most common element on Earth) – and rice is particularly efficient at extracting it from the irrigated soil in which it is grown.

Technically, arsenic compounds exist as both organic and inorganic forms – organic arsenic compounds contain one or more carbon atoms while inorganic arsenic compounds do not have any carbon atoms.

Inorganic arsenic compounds are much more common in soil and irrigation waters (and thus in rice) – and unfortunately, they are also significantly more toxic than organic arsenic compounds, especially the inorganic trivalent forms such as arsenic trioxide, sodium arsenite and arsenic trichloride.

Pentavalent inorganic arsenic compounds such as arsenic pentoxide, arsenic acid and arsenates (lead arsenate, calcium arsenate, et cetera) are less toxic and also pretty common but they can be metabolised into trivalent arsenic by human digestive systems.

A sobering example of arsenic poisoning is Bangladesh, where around 80 million people are affected by arsenic contamination. Around 43,000 people die each year in the country from this poison – and the symptoms are starkly summarised by an excerpt from a medical review published in 2011: “Chronic arsenic exposure is associated with many human health conditions, including skin lesions and cancers of the liver, lung, bladder and skin. It is also associated with many non-cancer health conditions, such as adverse reproductive outcomes, neurological disorders and impaired cognitive development in children.”

However, please note that not all the arsenic in Bangladesh is obtained from eating rice as much of the drinking water there is also severely contaminated. However, it does indicate the toxicity of arsenic, and led to the US Department of Food & Drug Administration (FDA) in 2016 acting to limit the maximum permitted level of inorganic arsenic to just 100 ppb (parts per billion) for infant rice cereals – probably because toxicity is linked to the amount of arsenic ingested relative to body weight.

The Environmental Protection Agency in the United States also limits the amount of inorganic arsenic in drinking water to just 10 ppb.

Regardless of the somber situation in Bangladesh, there is generally no need to worry too much about arsenic in rice as supplies are tested regularly for arsenic content, at least in Western countries.

If you are still concerned, a validated technique is to soak rice overnight in water and then cooking the rice using a 5 to 1 ratio of water to rice, then throwing away the excess water. This method eliminates arsenic content by 80%.

A curious application of arsenic is its use in chicken feed as it has been found that organic arsenic helps fight parasitic infections and promote tissue development (weight gain) in poultry.

The problem is that the ingested safe organic arsenic compounds gets metabolised into toxic inorganic arsenic compounds (methylated phenylarsenical metabolites) by the digestive system of chickens – as such, adding arsenic to chicken feed is now banned in both the European Union and the United States.

However, it seems that the practice of feeding organic arsenic to chickens is still prevalent in many other countries.

Antibiotics with your steak, sir?

More free but unwanted common additives are the antibiotics used in the farming of animals. The biggest concern is that such use promotes the resistance of mammalian bacteria to the antibiotics, many of which are also used in humans.

The good news is that the use in animals of many of these compounds is now banned in the EU (especially those compounds with human medical applications); the bad news is that they are still heavily administered in most other countries, including the United States.

The other problem is that ingesting food laced with antibiotics can also promote within humans, bacterial resistance to antibiotics – potentially rendering future treatment with the same types of antibiotics ineffective.

As an indication of the scale of the problem: in the United States, animals consume 70% of ALL medically-important antibiotics produced, compared to just 30% for humans – a scary statistic indeed from Britain’s Review of Antimicrobial Resistance published in December 2015.

The same concerns also apply to shrimps, prawns and other seafood, so much so that imports of such seafood from China and various Asian countries are subject to heavy restrictions in both the United States and the EU – the antibiotics used include nitrofurans and chloramphenicol.

A dash of pesticides in your greens?

Apart from potentially poisoning humans when ingested, pesticides can have a significant impact on local fauna. Some impacts are very serious – a class of insecticide called neonicotinoids or neonics have been found to kill bees and other pollinators. Without pollination of plants by these insects, much of the world’s ability to produce food crops, vegetables and fruits would be severely compromised – and it is such a grave problem that the EU has banned the use of the three most common neonics: imidacloprid, clothianidin and thiamethoxam.

Strenuous monitoring of pesticides in the EU has resulted in 97.4% of crops in 2013 testing below the Maximum Residue Limits (MRL) permitted – imported foods, on the other hand, are five times more likely to exceed the MRL.

Several pernicious pesticides which are heavily used abroad, including the United States, are also banned in the EU – examples are Paraquat (linked to Parkinson’s disease); 1,3-Dichloropropene (linked to human cancers); Glyphosate, also known as Round-Up (the most heavily used pesticide in the United States, banned in some EU countries, linked to several serious human diseases) and Atrazine (linked to cancers and birth defects).

Even so, the EU dispersed almost 400,000 tonnes of pesticides in 2015 – of which 173,000 tonnes are fungicides and bactericides, 131,000 tonnes are herbicides and moss killers while 21,000 tonnes are insecticides and acaricides.

In case you are curious, acaricides are chemicals used to kill ticks, mites and other members of the arachnid subclass Acari.

Clandestine additives

Unintended additives such as inorganic arsenic compounds, antibiotics and pesticides are never included in the list of ingredients of processed foods, even though they are often not destroyed by food processing. Presumably the costs and efforts associated with such additional disclosures are not practical for the food industry – even the food regulators do not seem interested in exposing such information.

The catalogue of such “free” hidden food additives can be a very long list, ranging from mercury and polychlorinated biphenyls (PCB) in deep sea fish, flesh colourants (eg. synthetic astaxanthin) in farmed seafood to Bisphenol A (BPA) accumulated in food from plastic containers.

Natural is not always natural

To make things more confusing, many foods labelled as “natural” may not always be natural in the sense that you and I would understand it. While the ingredients may all be from natural sources, it is not natural to have, for example, a compound such as E325 (sodium lactate) injected into chicken meat as a preservative.

The self-evident argument is that a chicken by itself will never have sodium lactate included in its natural configuration, even if E325 is itself derived from natural sources.

Still, these obvious facts do not stop many food producers from marketing their products as “made from natural ingredients” or some derivation of “natural product”.

Maltodextrin

If this series has prompted you to inspect processed food labels more carefully, you would very likely have come across a compound called maltodextrin – it is used so ubiquitously that it does not even have an E-number as it is considered by the food industry as a normal ingredient, such as fish or flour or meat.

Maltodextrin has some interesting properties – it is usually artificially derived from wheat, corn, rice or potato starches by enzymatic processes and can be produced in various molecular lengths by varying the number of glycosidic bonds of starch glucose molecules.

The length of maltodextrin molecules determine its sweetness, which is denoted by the Dextrose Equivalent (DE) scale of between 3 and 20 – the higher the DE, the shorter the maltodextrin molecule and the sweeter the compound. Above a DE of 20, maltodextrin is practically just short strands of simple glucose molecules and is often then called glucose syrup.

Regardless of the DE scale, maltodextrin is easily broken down during digestion into glucose – this can have a significant impact on blood sugar levels.

Hence over-consumption of maltodextrin is not really suitable for people with blood sugar control issues as it is not different from ingesting sugars – but often without any warning from the sweetness of food.

One reason why maltodextrin is so commonly used is that it is manufactured in many configurations which can substantially improve the “mouth feel” of food without adding any disagreeable flavours.

Here is how it works: At a DE of 3, maltodextrin is practically flavourless, and the long glucose chains would also exist in polymeric (or grouped, bunched-up) configurations – the lower the DE, the greater the polymerisation of maltodextrin molecules.

So the density and textures of maltodextrin can be controlled by adjusting the DE (or polymerisation) of the compound – long-polymer maltodextrin is even used as a fat substitute in low-fat meat products as it can have the mouth feel of fat.

As such, maltodextrin is a very versatile compound and used extensively as thickeners and fillers, matching the textures of the required processed food items. It can also be added to drinks to improve the specific gravity of liquids.

Foods with long-polymer maltodextrins also tend to last longer as its molecules cannot be broken down by bacteria or fungi easily (eg. the maltodextrin added to beers to increase specific gravity is not affected by the fermentation yeast) – hence it is also used as a preservative.

There are no known major toxicity issues with any molecular configuration of pure maltodextrin, primarily because eating this compound is the same as ingesting glucose.

However, concerns may arise from the lack of sweetness and ubiquity of maltodextrin – these factors might induce blood sugar-related health issues with unwary consumers.

Also, maltodextrin is derived from commercial starch sources which may have been contaminated by pesticides – which can then find their way into foods with the compound.

Hence, the nutrition labels on the tins and packages indicate the residual nutrients that should be present when you finally open the processed food container.

What is interesting is that, especially in hermetically-sealed tins, the further degradation of nutrients happens only very slowly inside the tin.

So a tin opened a year or more after production would have retained a high percentage of the nutrients that were present during canning.

In many ways it is remarkable that nutritious food can be preserved and presented in such a convenient format, considering how the original ingredients would have normally rotted away within a very short space of time.

However, cooking canned contents, as with cooking fresh foods, would also result in some loss of nutrients (especially vitamins) due to the heat involved.

The nutrition panel

In the EU, all packaged foods now require a nutrition panel to indicate the nutrients in the products. The nutrition panels in Europe are different from those in the United States and other countries because of the different standards and legal requirements in various countries.

Some additional useful information is also sometimes offered voluntarily by large food suppliers, such as colour-coded tags for sugar, fats and salt related to a product (Picture 2 – note that the percentage numbers at the bottom indicate percentages of the daily adult recommended amounts for the respective food groups). And you will need a colour-code interpretation chart (Picture 1) to understand what it all actually means.

But generally, you are much more likely to see less friendly nutrition panels such as the following (Picture 3).

Picture 3: Example food nutrition panel.

Obviously, the important things to note about this label and other food nutrition panels are the calories, sugar and salt contents – note that in the EU, the unit “kcal” (kilocalorie) is used to represent 1,000 calories whereas in the United States, the unit used is “Cal” (Calorie).

The World Health Organisation (WHO)’s over-generous daily guideline for sugar consumption is 25g and consuming 100g of this food item would be consuming over a third of that daily sugar limit.

The WHO also recommends a limit of 6g of salt a day and 100g of this food would be over a tenth of that amount.

As you go through various meals, it would be helpful to keep a running total of the calories, sugars and salt that you are consuming and ensure that you keep within reasonable limits for the day as often as possible.

What is interesting about the Fats information in this example label is what it is NOT telling you.

If you sum up the saturates, mono-unsaturates and polyunsaturates, the total comes to 3.6g, which is 0.2g less than the total of 3.8g. The difference is almost certainly due to unreported trans-fats, a particularly unhealthy fat to ingest but very convenient for use in processed foods. On this basis alone, I would personally not eat this food item.

And this series sums up what I look for and understand from the data gleaned when I scrutinise ingredient lists and nutrition labelling. Although it is always preferable to cook fresh foods, often it is exigent to get some nutritious packaged food which can save time and effort.

Processed food is not always automatically bad for health – and often they can taste quite good too, which always seems a bit of a miracle considering the heavy processing they must undergo before arriving in a tin in front of you.

But at least, you now have a better idea how and why.

This ends our series on food labels. Next up is the science of ageing beef and a couple of experiments you can do at home to improve your steak.

3 Comments

RayL

A epic series which truly makes you think of comercial food as it is full of real information and worthy of a university thesis degree already by itself. Makes you realise the rubbish we eat without even knowing. Chris should be Food Minister. Thanks to Star for very good series.

AS

It was long to read all the parts and to appreciate a real good piece of food science journalism. This is the only column worth reading about food science anywhere in Asia and helped my family a lot already to change some bad habits. But is this writer doing a 2-weekly column because if so we are missing the next column? Thank you for your always interesting articles.

Eunice

It took several days to read all the elements of this series and the detail and amount of research done by the author is impressive. It has been very helpful to us as food researchers and especially the last part which connects everything together cleverly. I seldom bother to comment on such articles but this is an exceptional column. Thanks from Southampton, UK

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